1. Technical Field
The present invention relates to a charging element device equipped in electric cars, hybrid electric cars, and the like, as a driving power supply. The invention relates to any type of charging element device, including cells such as nickel hydrogen battery and lithium batteries and energy storage devices such as double layered capacitors (ultra-capacitors).
2. Background Art
With respect to this type of charging element device, a conventional one is generally known in which an inner element having a positive electrode and a negative electrode is housed in a battery case with a positive electrode terminal and a negative electrode terminal being installed through current collector plates connected to the respective electrodes of the inner element. Such charging element devices are classified to those in which the positive and negative terminals are divided and located on the respective ends of the battery case and those in which the terminals are collectively located on one end. Furthermore, an electrolyte solution is sealed in the battery case and a safety valve is located so as to prevent the battery case from rupturing. For example, in charging or discharging, the generated gas becomes excessive to increase the inner pressure, the safety valve breaks, thereby preventing the battery case from rupturing.
Conventionally, in those charging element devices with the positive and negative terminals being located at both ends in a divided manner, an electrolyte solution inlet and the safety valve are formed on one end. Moreover, in those charging element devices with the positive and negative terminals being collectively located on one end, some of them have the electrolyte solution inlet and the safety valve on the terminal side, and others have the electrolyte solution inlet on the terminal side with the safety valve being located on the other side.
FIG. 7 shows an example of the conventional charging element device in which the positive and negative terminals are collectively located on one end of a battery case with the electrolyte solution inlet and the safety valve being located on the terminal side. In this Figure, reference numeral 100 is a cylindrical battery case with a bottom, 101 is an inner element having positive and negative electrodes with current collector plates 102, 103 being connected to these electrodes, 104 is a sealing plate with a positive terminal 105, a negative terminal 106 and a safety valve 107 located therein. This charging element device is assembled such that: the inner element 101 is housed inside the battery case 100; an electrolyte solution is charged into the battery case 100 through an opening of the battery case 100; the sealing plate 104 is set on the opening of the battery case 100 with the respective terminals 105, 106 being connected to the current collector plates 102, 103; and the circumference of the opening of the battery case 100 is crimped over the sealing plate 104. In this case, the opening of the battery case 100 serves as the electrolyte solution inlet, and the opening is sealed by the sealing plate 104.
In the charging element device shown in FIG. 7, when the safety valve 107 is activated and opened with the electrolyte solution leaking therefrom, the electrolyte solution flows over the positive and negative terminals 105 and 106, and tends to cause short-circuiting via the electrolyte solution. Reference numeral L shows such an electrolyte solution short-circuiting the terminals 105 and 106. This short-circuiting may also occur if the electrolyte solution leaks from the opening of the battery case.
Moreover, in the case of the charging element device in which the electrolyte solution inlet is located at the terminal side and the safety valve is located on the other side, most of those element devices have a construction in which one portion of the bottom of the battery case 100, as shown in FIG. 7, is formed as a thin portion which serves as a safety valve. However, in such cases, the battery case 100 comes to rupture, resulting in a difficulty in controlling the electrolyte solution leaking and scattering, and consequently causing damages to peripheral devices by the scattering electrolyte solution.
Therefore, an objective of the present invention is to provide a charging element device and a holding structure therefore, which can prevent terminals from short-circuiting due to leaked electrolyte solution, and deal with the leaked electrolyte solution safely without scattering over peripheral devices.
The present invention provides a charging element device comprising: a positive electrode terminal and a negative electrode terminal which are located at one end of a cylindrical battery case having a positive electrode and a negative electrode equipped therein and which are respectively connected to the positive electrode and the negative electrode, with an electrolyte solution charging opening being formed at the other end of the battery case. The electrolyte solution charging opening is sealed by a plug having a safety valve, and the safety plug reduces an inner pressure of the battery case when the inner pressure is not less than a predetermined pressure.
In accordance with the charging element device of the present invention, the electrolyte solution charging opening and the safety valve which tend to have a leakage of the electrolyte solution and the terminals are located at different ends in a divided manner. Therefore, the terminals are free from short-circuiting by the electrolyte solution leaking from the electrolyte solution charging opening and the safety valve.
The present invention further provides a holding structure for the above-mentioned charging element device, which houses the charging element device inside an external case and holding it therein. The charging element device is supported in a condition in which the charging element device is located in the external case with the plug facing downward, and an electrolyte solution discharging path, which is isolated from the charging element device and is communicated with the inside of the battery case when the safety valve is opened, is provided in the external case.
In accordance with the holding structure for the charging element device of the present invention, the plug provided with the safety valve is located downward. Therefore, when the safety valve is activated and opened, the lea king electrolyte solution flows downward. When the electrolyte solution leaks, it flows into the electrolyte solution discharging path. Since the electrolyte solution discharging path is isolated from the charging element device, the electrolyte solution does not adhere to the terminals, thereby making it possible to prevent short-circuiting between the terminals as well as scattering of the solution over peripheral devices, and consequently to safely dispose of the electrolyte solution.
In the above-mentioned holding structure of the present invention, it is preferable to provide an arrangement in which an electrolyte solution discharging path is provided with an electrolyte solution detecting device for detecting the electrolyte solution. Since the electrolyte solution is detected by the electrolyte solution detecting device, the safety valve is activated, namely, it is recognized an abnormal state of the charging element device, so that it is possible to exchange charging element device quickly.
Moreover, in the above-mentioned holding structure of the present invention, it is preferable to provide an arrangement in which a plurality of charging element devices are supported inside the external case while being series-connected to one after another, and electrolyte solution discharging paths are formed in the respective charging element devices. In this case, the plurality of charging element devices are series-connected to form a charging element module, and this module is held inside the external case. With an arrangement in which the electrolyte solution discharging paths are formed in the respective charging element devices with the electrolyte solution detecting device being located in these electrolyte discharging paths, it is possible to detect which charging element device has an activated safety valve, and consequently to provide an easier exchanging job.
Moreover, the present invention is designed to allow the electrolyte solution detecting device to release a detection signal (for example, an electric signal) upon detection of the electrolyte solution, and is more preferably provided with a warning device for giving a warning sign upon receipt of the detection signal. For example, in the case when the charging element device of the present invention is installed in an electric car or a hybrid electric car or the like as a driving power supply, the warning device serves as a device for providing a warning to the driver, which is constituted by lamps on the meter panel, buzzers, etc. In this arrangement, the user is, at once, informed of the fact that the safety valve is activated, that is, an abnormal state of the charging element device, so that it is possible to exchange charging element devices quickly.